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arXiv · 2609.33229

In-plane optimal qubit operation with control fidelities exceeding 99 %

Yu-Chen Zhou·Zhenzhen Kong·Rong-Long Ma·Hao-Tian Jiang·Ao-Ran Li·Yang Zhong·Zhi-Tao Wu·Rui Zheng·Gui-Lei Wang·Gang Cao·Hai-Ou Li·Guo-Ping Guo
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Abstract

Hole spin qubits based on semiconductor quantum dots are promising for building future large-scale quantum computers owing to their all-electrical manipulation. However, abundant physical mechanisms of valence band holes lead to anisotropic qubit properties. There is an opportunity to prolong the coherence time and achieve high-fidelity qubit manipulations. Here, we report a single-hole spin qubit in a planar germanium quantum dot and investigate its anisotropic susceptibility to charge noise under an in-plane magnetic field. By correlating the longitudinal spin-electric susceptibility with qubit coherence and control performance, we identify an optimal operating point where the sensitivity to charge noise is minimized. We find that optimizing the magnetic-field orientation reduces the spin-electric susceptibility, resulting in a five-fold enhancement of the Hahn-echo coherence time and a nearly tenfold suppression of control infidelity. At the optimal operating point, gate set tomography demonstrates the maximum gate fidelity of 99.82 %. Our finding enhances the prospects of hole spin qubits for scalable quantum information processing.

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Yu-Chen Zhou, Zhenzhen Kong, Rong-Long Ma, Hao-Tian Jiang, Ao-Ran Li, Yang Zhong, Zhi-Tao Wu, Rui Zheng, Gui-Lei Wang, Gang Cao, Hai-Ou Li, Guo-Ping Guo. 2026-09-27. In-plane optimal qubit operation with control fidelities exceeding 99 %. https://arxiv.org/abs/2609.33229

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